1. Technical Field
The present disclosure relates to a wind turbine comprising a plurality of construction sections.
2. Description of the Related Art
A modern and hence large wind turbine is usually assembled in situ from a large number of individual elements. Large construction sections, such as steel tower segments, rotor blades and the rotor hub are typically fastened to each other in many cases using releasable fastenings, in particular by bolting them to each other. A steel tower of a larger wind turbine, for example, may be assembled from a plurality of steel tower segments. In order to connect two steel tower segments, these typically have two circumferential flanges in their connection region, said flanges having a plurality of bores for connection by means of bolts and nuts. Such a flange may typically comprise more than 100 bores, so more than 100 bolts with associated nuts are accordingly used to connect two steel tower segments.
To produce the connection, the two steel tower segments typically are aligned one above the other, and the bolts with nuts are disposed, although usually these are not immediately fastened tight. Not until a second or later step are all the bolts and nuts tightened with the desired final strength. This is usually carried out for one bolt after the other until all the bolts of the respective flange have been tightened. Whether all the bolts are actually tightened or not depends at present on the alertness of the fitter on site. Since the bores and hence also the bolts are arranged uniformly in the flange with regard to both position and size, it can easily happen that a bolt is skipped or doubly tightened. In order to prevent this error from occurring, the number of bolts already tightened may be counted. However, this cannot solve the problem reliably because doubly tightened bolts would also be counted as two bolts, and conversely, when some bolts are skipped, other bolts are doubly tightened at the end of the tightening procedure, with skipped bolts thus being overlooked.
However, the stability of a wind turbine usually requires that all the bolts provided are also tightened, and the risk of some bolts not being tightened or not being correctly tightened also harbours the risk of destabilising the wind turbine in its construction. Similar problems may occur when connections between two construction sections of a wind turbine need to be retightened or checked at a later date. Such checking or retightening may be carried out when a service interval has elapsed, for example, or also when components are replaced.
At this point, reference is made in general to the following documents: DE 101 44 167 C1, DE 33 27 964 A1 and WO 00/63565 A1.